This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book analyses between sibling transference and parent/child transference. It shows that clinical material, the interweaving of the developmental strands between the types of transference. The book presents Anna Freud's view on siblings and addresses the question as to why siblings have been ignored in psychoanalytic theory. It explores Melanie Klein for a more fulsome picture of the impact of sibling relationships on the developing psyche and, importantly, the idea that it is through identification with children' siblings that adult heterosexuality is achieved. The book presents the concept of identification with siblings is further explored via the concept of brotherly love. Freud and Sophie Dann’s observation of six war-orphaned children emphasizes the importance of sibling/peer relationships in mental health. The book suggests that the case illuminates Freud’s own personal discovery of the meaning of the primal scene.